• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.357-364
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• 2014

The first mission for the IoT based hyper-connectivity communication is developing a device-to-device communication technique in infra-less low-power and lossy networks. In a low-power and lossy wireless network, IoT devices and routers cannot keep the original path toward the destination since they have the limited memory. Different from the previous light-weight routing protocols focusing on the reduction of the control messages, the proposed scheme provides the light-weight IPv6 address auto-configuration, IPv6 neighbor discovery and routing protocol in a IoT capable infra-less wireless networks with the bloom filer and enhanced rank concepts. And for the first time we evaluate our proposed scheme based on the modeling of various probability distributions in the IoT environments with the lossy wireless link. Specifically, the proposed enhanced RPL based light-weight routing protocol improves the robustness with the multi-paths locally established based on the enhanced rank concepts even though lossy wireless links are existed. We showed the improvements of the proposed scheme up to 40% than the RPL based protocol.

• Telecommunications review
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• v.24 no.5
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• pp.677-691
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• 2014

Connectivity is becoming more important keywords recently. For example, many devices are going to be connected to the internet. It is usually called as the IoT(internet of things). Many IoT devices can be evolved as a part of giant system of the world wide web. It is a great opportunity for us, because many new services can have emerged through this paradigm. In this paper, we propose a device virtualization framework for smart home service. The proposed framework connects the many home appliances devices and the internet using a dynamic protocol conversion. After our protocol conversion for device virtualization, our framework provides a RESTful API to access the resources of device through the internet. Therefore, the proposed framework can provide a variety of services, so it also can be developed into the ecosystem for smart home service. The current framework version only supports UPnP enabled devices of the home, but it can easily be extended to many other home middleware solutions. To verify the feasibility of the framework, we have implemented several service scenarios.

• Journal of Korea Spatial Information System Society
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• v.6 no.2 s.12
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• pp.39-49
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• 2004

An increasing number of distributed applications will be achieved with mobile technology. These applications face temporary loss of network connectivity when they move. They need to discover other hosts in an ad-hoc manner, and they are likely to have scarce resources including CPU speed, memory and battery power. Software engineers building mobile applications need to use a suitable middleware that resolves these problems and offers appropriate support for developing mobile applications. In this paper, we describe the meta-server building for middleware that addresses reflective context awareness and present usability with demonstration. Metadata is consist of user configuration, device configuration, user context, device context and dynamic image metadata. When middleware send a saving or retrieval request to meta-server, it returns messages to middleware after the verification of the request. This meta-server has the application for multimedia stream services with context awareness.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.511-519
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• 2017

This Paper introduces the design and communication method between PLC (Programmable Logic Controller) and Arduino based on MODBUS Protocol. MODBUS connection can be established in a new or existing system very easily, therefore we used this protocol in our proposed system. In the field of automatic devices, multi-function serial port such as RS232, RS422, RS485, and so on creates a great convenience to the developer. This proposed system used RS485 as a key mediator for data exchanging on a connected network. We also believe that it will reduce the development cost in various automated industry because this system can be reused or can be implemented any such PLC installed machines. RS485 is used as a communication interface between PLC (as a slave) and Arduino (as a master), through which a reliable network is created for safe and fast communication. Furthermore, RS485 allows multiple devices(up to 32) to communicate at half duplex on a single pair of wires and provides a long connectivity area (up to 1200 meters) as compare to other device, which makes it a user-friendly for various devices in the automated industry. Moreover, Arduino can play as a mediator by connecting third party device and setup a communication network with PLC.

• Smart Media Journal
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• v.5 no.4
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• pp.9-17
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• 2016

Over the next 20 years it will begin the exodus from the Internet and smart phones to the Internet of Things. The heart of IoT gives new utility and value with connectivity among things around people to the human. In future, Industrial environment will be intimately connect all among machines and machines or factories and factories in all processing, and by digitizing of all goods and production life-cycle, which is a combination of virtual world and real world, the digital factory will become reality eventually. The proposed IoT or IIoT based Download OTA (Over-the-Air) provides a flexible mechanism for downloading Media objects of any type and size from a network. Moreover, proposed IoT based DLOTA provides a part of security by lightweight encryption, OTP, and CapBAC technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2671-2676
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• 2015

Nowadays, Mobile devices are now capable of supporting a wide range of applications. Unfortunately, some of applications demand an ever increasing computational power and mobile devices have limited resources due to their constraints, such as low processing power, limited memory, unpredictable connectivity, and limited battery life. To deal with mobile devices' constraints, researchers envision extending cloud computing services to mobile devices using virtualization techniques to shift the workload from mobile devices to a powerful computational infrastructure. Those techniques consist of migrating resource-intensive computations from a mobile device to the resource-rich cloud, or server (called nearby infrastructure). In this paper, we want to highlight on cloudlet architecture (nearby infrastructure with mobile devices), its functioning and in our future work, analyze effects of distance between cloudlet and mobile devices.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.211-216
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• 2021

Information from various heterogeneous devices is steadily increasing in distributed cloud environments. This is because high-speed network speeds and high-capacity multimedia data are being used. However, research is still underway on how to minimize information errors in big data sent and received by heterogeneous devices. In this paper, we propose a deep learning-based asymmetric storage management technique for minimizing bandwidth and data errors in networks generated by information sent and received in cloud environments. The proposed technique applies deep learning techniques to optimize the load balance after asymmetric hash of the big data information generated by each device. The proposed technique is characterized by allowing errors in big data collected from each device, while also ensuring the connectivity of big data by grouping big data into groups of clusters of dogs. In particular, the proposed technique minimizes information errors when storing and managing big data asymmetrically because it used a loss function that extracted similar values between big data as seeds.

• Progress in Superconductivity and Cryogenics
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• v.10 no.4
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• pp.23-28
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• 2008

As a part of the plasma control system (PCS) for the first plasma campaign of KSTAR, seven sets of fast feedback control loop for the superconducting poloidal field magnet power supply (PF MPS) have been implemented. A special real-time digital communication interface has been developed for the simultaneous exchanges of the current/voltage data from the 7 sets of 12-thyristor power supplies in a 200 microsecond control cycle. Preliminary power supply tests have been performed before actual cooldown of the device. A $29mH/50m{\Omega}$ solenoid dummy has been fabricated for a series of single power supply tests. Connectivity and response speed of the plasma control system have been verified. By changing hardware cabling, this load was also used to estimate mutual inductance coupling effects of two geometrically adjacent solenoid coils on each power supply. After the cooldown was complete, each pair of the up/down symmetric PF coils has been serially connected and tested as part of the device commissioning process. Bipolar operation and longer pulse attempts have been investigated. The responses of the coils and power supplies corresponding to the plasma magnetic controls in plasma discharges are also analyzed for the future upgrades.

• Journal of Korea Multimedia Society
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• v.15 no.1
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• pp.108-114
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• 2012

Government-related organizations and institutions are stepping up their efforts to establish information system and service for disaster prevention because of the increasing occurrence of disaster. Therefore, they are collecting numerous disaster data using various way such as using mobile device or disaster history document. However, these method requires large amount of time and effort. Moreover, it is difficult to connects with another system because previous ways fall short of standard and connectivity. Therefore, this paper focused on collecting various disaster information using smartphone application and then complement the drawbacks of previous system.

• Journal of Information Technology Applications and Management
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• v.12 no.4
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• pp.93-104
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• 2005

Recently, RFID/USN is one of fundamental technologies in information and communications networks. Low-Rate WPAN, IEEE802.15.4 is a low-cost communication network that allows wireless connectivity in applications with limited Power and relaxed throughput requirements. Its applications are building automation, personal healthcare, industrial control, consumer electronics, and so on. Some applications require location information. Of course location awareness is useful to improve usability of data Low-Rate WPAN Is regarded as a key specification of the sensor network with the characteristics of wireless communication, computing, energy scavenging, self-networking, and etc. Unfortunately ZigBee alliance propose a lot of applications based on location aware technologies, but the specification and low-rate WPAN devices don't support anything about location-based services. RSSI ( Received Signal Strength indication) is for energy detection to associate, channel selection, and etc. RSSI is used to find the location of a potable device in WLAN. In this paper we studied indoor location awareness using vector matching of RSSI in low-Rate wireless PAN. We analyzed the characteristics of RSSI according to distance and experimented location awareness. We implemented sensor nodes with different shapes and configured the sensor network for the location awareness with 4 fixed nodes and a mobile node. We try to contribute developing location awareness method using RSSI in 3-dimension space.